1. Field of the Invention
The present invention relates to the field of glass neon filament constructions for commercial neon signs. More particularly the present invention relates to the field of supporting glass neon tubes with glass tube supports.
2. Description of Prior Art
Glass neon filament constructions have been used for commercial signs for many years. Most typical structures of commercial neon signs use a multiplicity of glass neon tubes connected together. One of the difficult problems in the construction is how to support the glass tubes and hold them into position. Retaining a glass tube onto a tube support is a common issue in the glass tubular lamp industry. The following is a list of the prior art patents which have addressed to this problem.
1. U.S. Pat. No. 4,122,511 issued to Petersen on Oct. 24, 1978 for "Lamp-Shade For Tubular Lamps" (hereafter the "Petersen Patent.revreaction.).
2. U.S. Pat. No. 2,885,538 issued to Mahon et al. on May 5, 1959 for "Neon Tubing Support" (hereafter the "Mahon Patent").
3. British Patent No. 684,186 issued and assigned to The Edison Swan Electric Company Limited on Aug. 29, 1951 for "Improvements In And Relating To Lanterns For Street Lighting" (hereafter the "British Patent").
4. U.S. Pat. No. 2,254,706 issued to Mueller et al. on Sept. 2, 1941 for "Fluorescent Lamp Holder" (hereafter the "Mueller Patent").
5. Australian Patent No. 107,958 issued and assigned to The General Electric Company Limited of England on July 27, 1939 for "Improvements In Lighting Fittings Adapted To Corporate With A Linear Source Of Light" (hereafter the "Australian Patent").
The Petersen Patent discloses a lamp-shade for tubular lamps. The primary concept of the Petersen Patent is to provide a lamp-shade which produces a distribution of light in a preferred manner. It comprises a plurality of cross plates 24 with saw-tooth shaped surfaces on both sides which are primarily used for distributing the light in a preferred manner. In addition each one of plates 24 also has two supporting rods 34 to support the tubular lamp. However the plate structure with saw-tooth shaped surfaces is not only unnecessary but also not applicable for supporting glass neon tubes of commercial neon signs.
The Australian Patent discloses a directional lighting fitting. The primary concept of the Australian Patent is also to provide a lighting fitting which produce a distribution of light with maximum intensity in a preferred direction. Nevertheless the Australian Patent discloses a device combined by a stirrup and a spring for supporting one end of a tubular lamp. The lighting fitting comprises a tubular lamp supported at one end by socket 4 and the other end by stirrup 11 which is closed by spring 12. Spring 12 has both its ends attached to the two outwardly extended ends of stirrup 11 and therefore forms a closed loop around the outer diameter of the end of the tubular lamp.
The British Patent discloses an improved street lighting lantern for an elongated tubular light source. The primary concept of this British Patent is similar to the one of the Australian Patent discussed above. The British Patent also discloses a hook support 25 with a spring to steady the unfastened end of a tubular lamp in the operable position.
The Mueller Patent discloses a fluorescent lamp holder comprising a body provided with spaced contact members for engaging the spaced contact prongs of a fluorescent lamp, and a bail 17 having opposite ends 12 pivotally mounted on opposite sides of the body and having a portion adapted to extend the periphery of the lamp for retaining it in position on the lamp holder. It takes two holders to hold an elongated tubular lamp at its two ends, one at each end of the lamp. The contact prongs at each end of the lamp are inserted into the contact members on the body of the holder at each end respectively. The impinging contact between the prongs at the ends of the lamp and the contact members on the body of the holders, and the inward longitudinal spring effect of the body of the holders at each end of the lamp primarily hold the lamp in position. While this is sufficient to retain the lamp, which is true today, it was felt back in the 1940's that an additional support was needed. Therefore bail 17 was added. As described in the Mueller Patent, two ends 12 of bail 17 are pivotally mounted to the opposite sides of the body of the holder respectively. Bail 17 can be rotated about a transversal axis which is through its two ends 12 and perpendicular to the longitudinal direction of the elongated lamp. Before inserting an end of the lamp into the body of a holder, bail 17 is rotated about the transversal axis into an open position to leave enough clearance for putting the end of the lamp into the body of the holder. After the end of the lamp has been inserted into the body of the holder, bail 17 is rotated back into a locking position so bail 17 with its two ends mounted to the body of the holder forms a closed loop with its extended portion engaged to the outer periphery of the end of the lamp.
Although the Australian Patent, the British Patent and the Mueller Patent all disclose some sort of means for supporting an elongated tubular lamp, it needs to be pointed out that all the supporting means are forming a closed loop around the outer circumference of the tubular lamp. This kind of closed loop arrangement is only suitable for supporting a tubular lamp at the end but not suitable to support an elongated tubular lamp at the middle. This is because without completely detaching either the springs of the Australian Patent and British Patent or the bail of the Mueller Patent to break the closed loop, the middle part of an elongated tube cannot be placed into and enclosed by the closed loop. Therefore these types of supporting means are not suitable for constructing commercial neon signs because they use a lot of elongated glass neon tubes which need to be supported not only at the ends but along everywhere in the middle.
The Mahon Patent discloses a type of neon tube support which addresses this problem. It comprises a supporting clip 22 mounted to a holder. Clip 22 has an end provided with a bifurcated arm structure having arms 44 which diverge away from the shank of clip 22 and converge toward one another so that their ends are located adjacent to but spaced from one another so a portion of an elongated glass tube may be snapped between them. This arrangement can support any portion of an elongated tube because instead of having a closed loop structure, it has an open clipping structure.
There is another type of prior art glass neon tube supporting means widely used today in constructions of commercial neon signs. Referring to FIG. 1 of the prior art, there is shown at 10 a portion of an elongated glass neon tube used for the structure of a commercial neon sign. Tube 10 is supported by a tube support 20 mounted to a base 30. Support 20 is made of glass for isolating purposes. Base 30 may be part of an outside wall or an inclined roof of a building or a backing board or structure of the sign. FIG. 2 is a cross-sectional view taken along line 2--2 of FIG. 1. Support 20 has a depressed top 22 for tube 10 to rest on and two downwardly extended side arms 24 and 26. A flexible wire 40 is wrapped around the outer circumference of tube 10 and two ends of wire 40 are tied to side arms 24 and 26 of support 20 respectively to securely retain tube 10 onto support 20. This type of glass neon tube supporting means can support any portion of an elongated glass neon tube, whether at the end or in the middle. It also has very few simple parts so it is less expensive to produce and easy to maintain. However in practical use of commercial sign construction, using flexible wires to wrap and tie the tube to the supports is very inconvenient and is a very time consuming process. It will be beneficial if there is a clamping device which can be utilized with the current glass tube supports to clamp the outer circumference of an elongated glass tube for retaining the elongated glass tube onto the glass tube support in commercial neon sign constructions.